The invention relates to a vehicle occupant restraint system.
An occupant restraint system known from DE 298 06 200 comprises a piston housed in the distributor pipe, which piston is displaced by the gas generator which also serves for inflating the gas bag. A rod mounted to the piston projects out from the distributor pipe and in the case of restraint is pressed out from the distributor pipe still further, whereby a gas bag, which is fastened t o the rod, is tensioned.
The invention provides a vehicle occupant restraint system in which a rod, stressed with regard to thrust and bending, can be avoided as power transmission means. This is achieved in a vehicle occupant restraint system which comprises an inflatable gas bag, a gas-carrying distributor pipe projecting into the gas bag and a piston housed displaceably in the distributor pipe. The restraint system further comprises a power transmission means which connects the piston and the gas bag with each other, which is constructed as a traction means, and via which a force for tensioning the gas bag is transferred onto the latter. Further, a deflection member for the power transmission means is provided in the distributor pipe. Through the provision of an integrated deflection member, it is possible to use a flexible traction means and to draw it by means of the expanding gas further into the distributor pipe, although the moving piston moves outwards. In the process, advantageously a tensioning cable can be used as traction means.
The deflection member deflects the traction means through approximately 180xc2x0 and advantageously extends through an opening in the piston in which it is displaceable. The traction means leaves the distributor pipe preferably at one of its ends, so that no additional openings which are to be sealed have to be provided in the distributor pipe.
So that the traction means is positioned exactly in the distributor pipe and also remains there during the tensioning process, one or more traction means guides can be provided in the distributor pipe, which can be formed for example in one piece on the distributor pipe.
Preferably, a deflection sheave comes to be used as deflection member, so that as few friction losses occur as possible.
According to the preferred embodiment, the occupant restraint system is a side occupant restraint system with a head-side gas bag having a large area, which serves for the at least partial covering of a side window of a vehicle. The distributor pipe extends along the roof frame of the vehicle.
In the region of a vehicle column, according to the preferred embodiment a further deflection member is provided for the traction means, from which deflection member the traction means extends to the gas bag. The gas bag is tensioned between fastening points, preferably at its opposite ends, at least one of the fastening points being formed by the traction means.
By the invention it is possible to hold the head gas bag, which has a large area, tensioned over several seconds, for example during an overturn of the vehicle, if a portion of the gas has already escaped from the gas bag.